1. SEAGRASSES IN MISSISSIPPI SOUND
Robin K. McCall
The University of Southern Mississippi
Gulf Coast Research Laboratory
Center for Fisheries Research and Development

2. SEAGRASSES
Believed to have come from terrestrial plants that returned to the sea by gradual, progressive steps of acclimation to shallow fresh water, to shallow brackish water, and finally to submersion in marine water
Presently 58 species, in 12 genera

3. SEAGRASSES Flowering plants (angiosperms) that live underwater
Reproduce by seed or vegetative expansion
The depths at which seagrasses occur is limited by water clarity, which determines the amount of light reaching the plant

4. MORPHOLOGICAL PATTERNS
Turtle grass
(Thalassia testudinum)
Widgeon grass
(Ruppia maritima)
Star grass
(Halophila englemanii)
Manatee grass
(Syringodium filiforme)
Shoal grass
(Halodule wrightii)

5. BIOLOGICAL FUNCTIONS
Nursery/habitat during some or all stages in the life cycle of marine fish & invertebrates
Relatively high rate of primary production drives detritus-based food chains
Directly consumed by birds, dugongs and turtles
Biological indicators of deteriorating water quality

6. PHYSICAL FUNCTIONS Reduce current velocity Dampen wave intensity
Increased water clarity
Dampen wave intensity
Reduced shoreline erosion
Stabilize marine sediments

7. HUMAN APPLICATIONS Insulation Roofing thatch Binding soil
Stuffing and packaging
Manure, stock feed supplement, minerals
Weaving, fiber products, paper-making
Food

8. ANTHROPOGENIC IMPACTS
Decreased water quality
Elevated nutrients
Increased turbidity
Contaminants
Biotic and abiotic stressors
Seasonal storm events (hurricanes)
Bioturbation
Disease
Propeller / anchor damage

9. PROPELLER SCARRING Damage to root/rhizomes can take up to seven years
to heal

10. EPIPHYTE GROWTH
Encrusting algae
Filamentous algae
Colonial algae

11. SEAGRASSES in MS SOUND Past 5 Species
Halodule wrightii
Halophila engelmannii
Ruppia maritima
Syringodium filiforme
Thalassia testudinum
Areal coverage in 1969: 12,000 acres
(Eleuterius 1973)
Present
2 Species
Areal coverage in 1998: 1,998 acres
(Moncreiff et al. 1998)

12. SHOAL GRASS (Halodule wrightii)
Stress tolerant “Pioneer”
species (elevated nutrients,
disturbance)

13. WIGEON GRASS (Ruppia maritima)
Stress tolerant
(low salinity, eleveated
nutrients, disturbance)

14. TURTLE GRASS (Thalassia testudinum)
“Climax” species
- Often requires sediment
modification by another
seagrass species
- Not tolerant of low salinity,
low light, or high nutrient load

15. SEAGRASS RESTORATION in MS Sound
Justification: turtle grass was historically present
Why/How was it removed:
Hurricane Camille
Extended periods of low salinity
Why is it not presently here: recruitment-limited
Light levels equivalent to that in Big Lagoon, FL
Epiphyte load not more than in Big Lagoon, FL

16. MISSISSIPPI SOUND

17. RESTORATION METHODS Collect and germinate seeds, plant seedlings
J.E.B.
Jim’s Environmental Boat
Collect and germinate seeds, plant seedlings
Remove seagrass “plugs” from donor bed
Propagate new shoot material from root/rhizome fragments

18. PROJECT OVERVIEW Granting agencies Volunteer labor Planting material
NOAA / Gulf of Mexico Foundation
National Park Service
Volunteer labor
Public participation (“ownership”)
Environmental education
Planting material
Big Lagoon, Florida
Chandeleur Islands, Louisiana

19. RESEARCH ASPECT Different water depths (light availability)
Plant within and outside of existing seagrass patches (biotic site preparation)
Varying light levels for shoot propagation of root/rhizome fragments

20. POTENTIAL ECOLOGICAL BENEFITS
Enhanced habitat for local marine species
Increase in number and biomass of commercially and recreationally important fish and shellfish
Reduced erosion along the northern edge of the barrier island chain

21. POTENTIAL ECONOMIC / AESTHETIC BENEFITS
Income from recreational fishermen
Enhanced shrimp production
Bay scallop fishery (e.g. St. Joseph Bay, FL)
Increased water clarity
Ecotourism

22. RECOMMENDATIONS Continue efforts to improve water quality
Restrict activities which are destructive to seagrass ecosystems
Public education

23. Clean Water Promotes Healthy Ecosystems